Olefin separator free li-ion battery

ABSTRACT

Implementations of the present disclosure generally relate to separators, high performance electrochemical devices, such as, batteries and capacitors, including the aforementioned separators, and methods for fabricating the same. In one implementation, a method of forming a separator for a battery is provided. The method comprises exposing a metallic material to be deposited on a surface of an electrode structure positioned in a processing region to an evaporation process. The method further comprises flowing a reactive gas into the processing region. The method further comprises reacting the reactive gas and the evaporated metallic material to deposit a ceramic separator layer on the surface of the electrode structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/037,895, filed Jul. 17, 2018, which claims benefit of U.S.Provisional Patent Application Ser. No. 62/546,824, filed Aug. 17, 2017,which is incorporated herein by reference in its entirety.

BACKGROUND Field

Implementations of the present disclosure generally relate toseparators, high performance electrochemical devices, such as, batteriesand capacitors, including the aforementioned separators, and methods forfabricating the same.

Description of the Related Art

Fast-charging, high-capacity energy storage devices, such as capacitorsand lithium-ion (Li-ion) batteries, are used in a growing number ofapplications, including portable electronics, medical, transportation,grid-connected large energy storage, renewable energy storage, anduninterruptible power supply (UPS).

Li-ion batteries typically include an anode electrode, a cathodeelectrode, and a separator positioned between the anode electrode andthe cathode electrode. The separator is an electronic insulator, whichprovides physical and electrical separation between the cathode and theanode electrodes. The separator is typically made from micro-porouspolyethylene and polyolefin. During electrochemical reactions, i.e.,charging and discharging, Li-ions are transported through the pores inthe separator between the two electrodes via an electrolyte. Thus, highporosity is desirable to increase ionic conductivity. However, some highporosity separators are susceptible to electrical shorts when lithiumdendrites formed during cycling create shorts between the electrodes.

Currently, battery cell manufacturers purchase separators, which arethen laminated together with anode and cathode electrodes in separateprocesses. Other separators are typically made by wet or dry extrusionof a polymer and then stretched to produce holes (tears) in the polymer.The separator is also one of the most expensive components in the Li-ionbattery and accounts for over 20% of the material cost in battery cells.

For most energy storage applications, the charge time and capacity ofenergy storage devices are significant parameters. In addition, thesize, weight, and/or expense of such energy storage devices can besignificant limitations. The use of currently available separators has anumber of drawbacks. Namely, such available materials limit the minimumsize of the electrodes constructed from such materials, suffer fromelectrical shorts, involve complex manufacturing methods, and expensivematerials. Further, current separator designs often suffer from Lithiumdendrite growth, which may lead to short-circuits.

Accordingly, there is a need in the art for faster charging, highercapacity energy storage devices with separators that are smaller,lighter, and can be more cost effectively manufactured.

SUMMARY

Implementations of the present disclosure generally relate toseparators, high performance electrochemical devices, such as, batteriesand capacitors, including the aforementioned separators, and methods forfabricating the same. In one implementation, a method of forming aseparator for a battery is provided. The method comprises exposing ametallic material to be deposited on a surface of an electrode structurepositioned in a processing region to an evaporation process. The methodfurther comprises flowing a reactive gas into the processing region. Themethod further comprises reacting the reactive gas and the evaporatedmetallic material to deposit a ceramic separator layer on the surface ofthe electrode structure.

In another implementation, a method of forming a battery is provided.The method comprises depositing a ceramic separator layer on a surfaceof a positive electrode structure. The ceramic separator layer isdeposited on the surface of the positive electrode structure by exposinga metallic material to be deposited on the surface of the positiveelectrode structure to an evaporation process, flowing a reactive gasinto the processing region, and reacting the reactive gas and theevaporated metallic material to deposit the ceramic separator layer. Thepositive electrode structure is joined with a negative electrode withthe ceramic separator layer therebetween.

In yet another implementation, a method of forming a battery isprovided. The method comprises depositing a ceramic separator layer on asurface of a negative electrode structure. The ceramic separator layeris deposited on the surface of the negative electrode structure byexposing a metallic material to be deposited on the surface of thenegative electrode structure to an evaporation process, flowing areactive gas into the processing region, and reacting the reactive gasand the evaporated metallic material to deposit the ceramic separatorlayer on the negative electrode structure. The negative electrodestructure is joined with a positive electrode with the ceramic separatorlayer therebetween.

In yet another implementation, a method of forming a battery isprovided. The method comprises depositing a first ceramic separatorlayer on the surface of a positive electrode structure. The ceramicseparator layer is deposited on the surface of the positive electrodestructure by exposing a metallic material to be deposited on the surfaceof the positive electrode structure to an evaporation process, flowing areactive gas into the processing region, and reacting the reactive gasand the evaporated metallic material to deposit the ceramic separatorlayer. The method further comprises depositing a second ceramicseparator layer on the surface of a negative electrode structure. Thesecond ceramic separator layer is deposited on the surface of thenegative electrode structure by exposing a metallic material to bedeposited on the surface of the negative electrode structure to anevaporation process, flowing a reactive gas into the processing region,and reacting the reactive gas and the evaporated metallic material todeposit the second ceramic separator layer on the negative electrodestructure. The positive electrode and the negative electrode are joinedtogether to form the battery.

In yet another implementation, a method of forming a separator for abattery is provided. The method comprises exposing a metallic materialto be deposited on a surface of an electrode structure positioned in aprocessing region to an evaporation process. The method furthercomprises flowing a reactive gas into the processing region. The methodfurther comprises reacting the reactive gas and the evaporated metallicmaterial to deposit a ceramic separator layer on the surface of theelectrode structure. Flowing the reactive gas into the processing regioncomprises flowing moist oxygen into the processing region.

In yet another implementation, a method of forming a battery isprovided. The method comprises depositing a ceramic separator layer on asurface of a negative electrode structure. Depositing the ceramicseparator layer further comprises exposing a metallic material to bedeposited on the surface of the negative electrode structure positionedin a processing region to an evaporation process. Depositing the ceramicseparator layer further comprises flowing a reactive gas into theprocessing region. Depositing the ceramic separator layer furthercomprises reacting the reactive gas and the evaporated metallic materialto deposit the ceramic separator layer on the surface of the negativeelectrode structure, wherein flowing a reactive gas into the processingregion comprises flowing moist oxygen into the processing region. Themethod further comprises joining the negative electrode structure with apositive electrode structure with the ceramic separator layertherebetween.

In yet another implementation, a method of forming a battery isprovided. The method comprises depositing a ceramic separator layer on asurface of a positive electrode structure. Depositing the ceramicseparator layer comprises exposing a metallic material to be depositedon the surface of the positive electrode structure positioned in aprocessing region to an evaporation process. Depositing the ceramicseparator layer further comprises flowing a reactive gas into theprocessing region. Depositing the ceramic separator layer furthercomprises reacting the reactive gas and the evaporated metallic materialto deposit the ceramic separator layer on the surface of the positiveelectrode structure. Flowing the reactive gas into the processing regioncomprises flowing moist oxygen into the processing region. The methodfurther comprises joining the positive electrode structure with anegative electrode structure with the ceramic separator layertherebetween.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description ofthe implementations, briefly summarized above, may be had by referenceto implementations, some of which are illustrated in the appendeddrawings. It is to be noted, however, that the appended drawingsillustrate only typical implementations of this disclosure and aretherefore not to be considered limiting of its scope, for the disclosuremay admit to other equally effective implementations.

FIG. 1 illustrates a cross-sectional view of one implementation of acell structure formed according to one or more implementations describedherein;

FIG. 2 illustrates a cross-sectional view of another implementation of acell structure formed according to one or more implementations describedherein;

FIG. 3 illustrates a cross-sectional view of yet another implementationof a cell structure formed according to one or more implementationsdescribed herein;

FIG. 4 illustrates a cross-sectional view of yet another implementationof a cell structure formed according to one or more implementationsdescribed herein;

FIG. 5 illustrates a process flow chart summarizing one implementationof a method for forming a cell structure according to one or moreimplementations described herein;

FIG. 6 illustrates a process flow chart summarizing one implementationof a method for forming an electrode structure according to one or moreimplementations described herein;

FIG. 7 illustrates a process flow chart summarizing one implementationof a method for forming an electrode structure according to one or moreimplementations described herein;

FIG. 8 illustrates a process flow chart summarizing one implementationof a method for forming an electrode structure according to one or moreimplementations described herein;

FIG. 9 illustrates a schematic view of a web tool for forming a ceramicseparator according to one or more implementations described herein;

FIG. 10A illustrates a scanning electron microscope (SEM) image ofuncoated cathode material;

FIG. 10B illustrates an SEM image of cathode material coated withaluminum oxide according to implementations described herein; and

FIG. 11 illustrates an SEM image of a schematic cross-sectional view ofa cell structure having a ceramic separator layer formed according toimplementations described herein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneimplementation may be beneficially incorporated in other implementationswithout further recitation.

DETAILED DESCRIPTION

The following disclosure describes separators, high performanceelectrochemical cells and batteries including the aforementionedseparators, and methods for fabricating the same. Certain details areset forth in the following description and in FIGS. 1-11 to provide athorough understanding of various implementations of the disclosure.Other details describing well-known structures and systems oftenassociated with electrochemical cells and batteries are not set forth inthe following disclosure to avoid unnecessarily obscuring thedescription of the various implementations.

Many of the details, dimensions, angles and other features shown in theFigures are merely illustrative of particular implementations.Accordingly, other implementations can have other details, components,dimensions, angles and features without departing from the spirit orscope of the present disclosure. In addition, further implementations ofthe disclosure can be practiced without several of the details describedbelow.

Implementations described herein will be described below in reference toa high rate evaporation process that can be carried out using aroll-to-roll coating system, such as TopMet™, SmartWeb™, TopBeam™ all ofwhich are available from Applied Materials, Inc. of Santa Clara, Calif.Other tools capable of performing high rate evaporation processes mayalso be adapted to benefit from the implementations described herein. Inaddition, any system enabling high rate evaporation processes describedherein can be used to advantage. The apparatus description describedherein is illustrative and should not be construed or interpreted aslimiting the scope of the implementations described herein. It shouldalso be understood that although described as a roll-to-roll process,the implementations described herein may be performed on discretepolymer substrates.

The term “about” generally indicates within ±0.5%, 1%, 2%, 5%, or up to±10% of the indicated value. For example, a pore size of about 10 nmgenerally indicates in its broadest sense 10 nm±10%, which indicates9.0-11.0 nm. In addition, the term “about” can indicate either ameasurement error (i.e., by limitations in the measurement method), oralternatively, a variation or average in a physical characteristic of agroup (e.g., a population of pores).

The term “crucible” as used herein shall be understood as a unit capableof evaporating material that is fed to the crucible when the crucible isheated. In other words, a crucible is defined as a unit adapted fortransforming solid material into vapor. Within the present disclosure,the term “crucible” and “evaporation unit” are used synonymously.

The currently available generation batteries, especially Li-ionbatteries, use porous polyolefin separators, which are susceptible tothermal shrinkage at elevated temperatures and may cause short betweenpositive and negative electrodes or the corresponding currentcollectors. In addition, some polyolefin separators have poorwettability issues. A ceramic coating on the separator helps to inhibitdirect contact between electrodes and helps to prevent potentialdendrite growth associated with Li metal. Current state of the artceramic coating uses wet coating (e.g., slot-die techniques) of ceramicparticles dispersed in a polymeric binder to make the composite and asolvent to make the slurry. The coating thickness is typically around 3microns including randomly oriented dielectric material bound togetherby a polymer leading to a random pore structure. The existing ceramicparticle coating method has difficulty in reducing tortuosity due tothis random orientation of ceramic particles. Further, it is difficultto reduce the thickness of current ceramic coatings using current wetcoating techniques. In order to compensate for the increased surfacearea of finer ceramic powder particles current wet coating techniquesinvolve increased amounts of both binder and solvent to decrease theviscosity of the slurry. Thus, the current wet coating techniques sufferfrom several problems.

From a manufacturing point of view, an in-situ deposition of a ceramiccoating with a dry method is preferred from both a cost and performancepoint of view. In the present disclosure, a thin, low ionic resistanceceramic coating is formed directly on a surface of a positive electrodeand/or a surface of a negative electrode, where the ceramic coating isformed by a dry method using reactive evaporation of metals or metalcompounds. Further, the ceramic coating can be tuned for the appropriatethickness, micro/nanostructure, multilayered structure, morphology, porestructure and pore/ceramic orientation.

Compared to conventional ceramic coated separators, the reactiveevaporation techniques described herein have at least one of thefollowing advantages: (1) thinner separators result in less inactivecomponent volume fraction and a corresponding increase in energy densityand less ionic resistance across the separator; (2) the control ofcoating thickness and morphology provides less tortuous pores leading tosuperior separator performance; (3) the pore surface of the ceramicenhances the ionic conductivity of the overall electrolyte; and (4)suitably engineered ceramic coated separator shall enhance X-raydetection to determine manufacturing defects; and (5) higher voltagestability and puncture resistance properties of the separator can beachieved by nanocomposite coating control. Lithium dendrite inhibitingproperties of ceramic-coated separator are enhanced by nanosurfaceengineering to achieve homogeneous lithium metal deposition andstripping during cycling.

Results achieved so far include (1) uniform 300 nanometer and 600nanometer thick AlO_(x) coating deposited on a positive electrode usingaluminum evaporation in a reactive oxygen environment; (2) the AlO_(x)coating adhesion seems to be good with scotch tape peeling tests; and(3) columnar AlO_(x) structure and crystallites are aligned verticallyin the ceramic separator layer.

FIG. 1 illustrates a cross-sectional view of one implementation of acell structure 100 formed according to implementations described herein.The cell structure 100 has one or more ceramic separator layer(s) 130formed according to implementations described herein. In someimplementations, the cell structure 100 is a Li-ion battery structure.Cell structure 100 has a positive current collector 110, positiveelectrode(s) 120 a, 120 b (collectively 120) formed on opposing sides ofthe positive current collector 110, one or more ceramic separatorlayer(s) 130 a-c (collectively 130), a negative current collector 150and negative electrode(s) 140 a, 140 b (collectively 140) formed onopposing sides of the negative current collector. Note in FIG. 1 thatthe current collectors are shown to extend beyond the stack, although itis not necessary for the current collectors to extend beyond the stack,the portions extending beyond the stack may be used as tabs. Inaddition, although dual-sided electrode structures are shown, theimplementations described herein are also applicable to single-sidedelectrode structures.

The current collectors 110, 150, on positive electrode 120 and negativeelectrode 140, respectively, can be identical or different electronicconductors. Examples of metals that the current collectors 110, 150 maybe comprised of include aluminum (Al), copper (Cu), zinc (Zn), nickel(Ni), cobalt (Co), tin (Sn), silicon (Si), manganese (Mn), magnesium(Mg), alloys thereof, and combinations thereof. In one implementation,at least one of the current collectors 110, 150 is perforated.Furthermore, current collectors may be of any form factor (e.g.,metallic foil, sheet, or plate), shape and micro/macro structure.Generally, in prismatic cells, tabs are formed of the same material asthe current collector and may be formed during fabrication of the stack,or added later. All components except current collectors 110 and 150contain lithium ion electrolytes.

The negative electrode 140 or anode may be any material compatible withthe positive electrode 120. The negative electrode 140 may have anenergy capacity greater than or equal to 372 mAh/g, preferably ≥700mAh/g, and most preferably ≥1000 mAh/g. The negative electrode 140 maybe constructed from a graphite, silicon-containing graphite (e.g.,silicon (<5%) blended graphite), a lithium metal foil or a lithium alloyfoil (e.g. lithium aluminum alloys), or a mixture of a lithium metaland/or lithium alloy and materials such as carbon (e.g. coke, graphite),nickel, copper, tin, indium, silicon, oxides thereof, or combinationsthereof. The negative electrode 140 comprises intercalation compoundscontaining lithium or insertion compounds containing lithium.

The positive electrode 120 or cathode may be any material compatiblewith the negative electrode 140 and may include an intercalationcompound, an insertion compound, or an electrochemically active polymer.Suitable intercalation materials include, for example,lithium-containing metal oxides, MoS₂, FeS₂, MnO₂, TiS₂, NbSe₃, LiCoO₂,LiNiO₂, LiMnO₂, LiMn₂O₄, V₆O₁₃ and V₂O₅. Suitable polymers include, forexample, polyacetylene, polypyrrole, polyaniline, and polythiophene. Thepositive electrode 120 or cathode may be made from a layered oxide, suchas lithium cobalt oxide, an olivine, such as lithium iron phosphate, ora spinel, such as lithium manganese oxide. Exemplary lithium-containingoxides may be layered, such as lithium cobalt oxide (LiCoO₂), or mixedmetal oxides, such as LiNi_(x)Co_(1−2x)MnO₂, LiNiMnCoO₂ (“NMC”),LiNi_(0.5)Mn_(1.5)O₄, Li(Ni_(0.8)Co_(0.15)Al_(0.05))O₂, LiMn₂O₄, anddoped lithium rich layered-layered materials, wherein x is zero or anon-zero number. Exemplary phosphates may be iron olivine (LiFePO₄) andit is variants (such as LiFe_((1−x))Mg_(x)PO₄), LiMoPO₄, LiCoPO₄,LiNiPO₄, Li₃V₂(PO₄)₃, LiVOPO₄, LiMP₂O₇, or LiFe_(1.5)P₂O₇, wherein x iszero or a non-zero number. Exemplary fluorophosphates may be LiVPO₄F,LiAlPO₄F, Li₅V(PO₄)₂F₂, Li₅Cr(PO₄)₂F₂, Li₂CoPO₄F, or Li₂NiPO₄F.Exemplary silicates may be Li₂FeSiO₄, Li₂MnSiO₄, or Li₂VOSiO₄. Anexemplary non-lithium compound is Na₅V₂(PO₄)₂F₃.

In some implementations, the positive electrode 120 is formed frompositive electrode particles. In some implementations, the positiveelectrode particles are coated to enhance higher voltage stability,interface compatibility with the electrolyte and longer battery cyclelife. The coating of the positive electrode particles may be performedby sol-gel techniques, dry coating of nano-particles on the positiveelectrode material, or atomic layer deposition (ALD) techniques.

In some implementations of a lithium ion cell according to the presentdisclosure, lithium is contained in atomic layers of crystal structuresof carbon graphite (LiC₆) at the negative electrode 140 and lithiummanganese oxide (LiMnO₄) or lithium cobalt oxide (LiCoO₂) at thepositive electrode 120, for example, although in some implementationsthe negative electrode 140 may also include lithium absorbing materialssuch as silicon, tin, etc. The cell, even though shown as a planarstructure, may also be formed into a cylinder by rolling the stack oflayers; furthermore, other cell configurations (e.g., prismatic cells,button cells) may be formed.

Electrolytes infused in cell components 120, 130 and 140 can becomprised of a liquid/gel or a solid polymer and may be different ineach. In some implementations, the electrolyte primarily includes a saltand a medium (e.g., in a liquid electrolyte, the medium may be referredto as a solvent; in a gel electrolyte, the medium may be a polymermatrix). The salt may be a lithium salt. The lithium salt may include,for example, LiPF₆, LiAsF₆, LiCF₃SO₃, LiN(CF₃SO₃)₃, LiBF₆, and LiClO₄,BETTE electrolyte (commercially available from 3M Corp. of Minneapolis,Minn.) and combinations thereof. Solvents may include, for example,ethylene carbonate (EC), propylene carbonate (PC), EC/PC,2-MeTHF(2-methyltetrahydrofuran)/EC/PC, EC/DMC (dimethyl carbonate),EC/DME (dimethyl ethane), EC/DEC (diethyl carbonate), EC/EMC (ethylmethyl carbonate), EC/EMC/DMC/DEC, EC/EMC/DMC/DEC/PE, PC/DME, andDME/PC. Polymer matrices may include, for example, PVDF (polyvinylidenefluoride), PVDF:THF (PVDF:tetrahydrofuran), PVDF:CTFE (PVDF:chlorotrifluoroethylene) PAN (polyacrylonitrile), and PEO (polyethyleneoxide).

In some implementations, the ceramic separator layer 130 comprises aporous (e.g., microporous) ceramic layer (e.g., a separator film) 130with pores. In some implementations, the ceramic separator layer 130 isnon-porous. In some implementations, the ceramic separator layer 130comprises a lithium-ion conducting material. The lithium-ion conductingmaterial may be a lithium-ion conducting ceramic or a lithium-ionconducting glass or liquid crystal. In some implementations, the ceramicseparator layer 130 does not need to be ion conducting, however, oncefilled with electrolyte (liquid, gel, solid, combination etc.), thecombination of porous ceramic and electrolyte is ion conducting. Theceramic separator layer 130 is, at least, adapted for preventingelectronic shorting (e.g. direct or physical contact of the anode andthe cathode) and blocking dendrite growth. The ceramic separator layer130 may be, at least, adapted for blocking (or shutting down) ionicconductivity (or flow) between the anode and the cathode during theevent of thermal runaway. The ceramic separator layer 130 should besufficiently conductive to allow ionic flow between the anode andcathode, so that current, in selected quantities, may be generated bythe cell. The ceramic separator layer 130 should adhere well to theunderlying electrode material, i.e. separation should not occur. Asdiscussed herein, the ceramic separator layer 130 is formed on theunderlying electrode using evaporation techniques.

The ceramic separator layer 130 comprises one or more ceramic materials.The ceramic material may be an oxide. The ceramic material may beselected from, for example, aluminum oxide (Al₂O₃), AlO_(x),AlO_(x)N_(y), AlN (aluminum deposited in a nitrogen environment),aluminum hydroxide oxide ((AlO(OH)) (e.g., diaspore ((α-AlO(OH))),boehmite (γ-AlO(OH)), or akdalaite (5Al₂O₃.H₂O)), calcium carbonate(CaCO₃), titanium dioxide (TiO₂), SiS₂, SiPO₄, silicon oxide (SiO₂),zirconium oxide (ZrO₂), MgO, TiO₂, Ta₂O₅, Nb₂O₅, LiAlO₂, BaTiO₃, BN,ion-conducting garnet, ion-conducting perovskite, ion-conductinganti-perovskites, porous glass ceramic, and the like, or combinationsthereof. In one implementation, the ceramic material is a materialselected from the group consisting of: porous aluminum oxide,porous-ZrO₂, porous-SiO₂, porous-MgO, porous-TiO₂, porous-Ta₂O₅,porous-Nb₂O₅, porous-LiAlO₂, porous-BaTiO₃, ion-conducting garnet,anti-ion-conducting perovskites, porous glass dielectric, orcombinations thereof. The ceramic separator layer 130 is a binder-freeceramic layer. In some implementations, the ceramic separator layer 130is a porous aluminum oxide layer.

In some implementations, the ceramic separator layer 130 may be alithium-ion conducting material. The lithium-ion conducting material maybe a lithium-ion conducting ceramic or a lithium-ion conducting glass orion conducting liquid crystal. The Li-ion conducting material may becomprised of one or more of LiPON, doped variants of either crystallineor amorphous phases of Li₇La₃Zr₂O₁₂, doped anti-perovskite compositions,Li₂S—P₂S₅, Li₁₀GeP₂S₁₂, and Li₃PS₄, lithium phosphate glasses, sulfideglasses, (1−x)LiI-(x)Li₄SnS₄, xLiI-(1−x)Li₄SnS₄, mixed sulfide and oxideelectrolytes (crystalline LLZO, amorphous (1−x)LiI-(x)Li₄SnS₄ mixture,and amorphous (x)LiI-(1−x)Li₄SnS₄ for example. In one implementation, xis between 0 and 1 (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and0.9). The Li-ion conducting material can be directly deposited on thelithium metal film using either a by Physical Vapor Deposition (PVD),Chemical Vapor Deposition (CVD), spray, doctor blade, printing or any ofa number of coating methods. A suitable method for some implementationsis PVD. In some implementations, the ceramic separator layer 130 doesnot need to be ion conducting, however, once filled with electrolyte(liquid, gel, solid, combination etc.), the combination of poroussubstrate and electrolyte is ion conducting.

In one implementation, the ceramic separator layer 130 is thelithium-ion conducting material and the lithium-ion conducting materialis selected from the group consisting of: LiPON, crystalline oramorphous phases of garnet-type Li₇La₃Zr₂O₁₂, LISICON (e.g.,Li_(2+2x)Zn_(1−x)GeO₄ wherein 0<x<1), NASICON (e.g.,Na_(1+x)Zr₂Si_(x)P_(3−x)O₁₂ wherein 0<x<3), lithium borohydride (LiBH₄),doped anti-perovskite compositions, lithium containing sulfides (e.g.,Li₂S, Li₂S—P₂S₅, Li₁₀GeP₂S₁₂ and Li₃PS₄), and lithium argyrodites (e.g.,LiPS₅X wherein x is CI, Br or I).

In some implementations, the ceramic separator layer 130 comprises fromabout 50 wt. % to about 100 wt. % of aluminum oxide based on the totalweight of the ceramic separator layer 130 (e.g., from about 75 wt. % toabout 100 wt. %; from about 85 wt. % to about 100 wt. % of aluminumoxide).

In some implementations, the ceramic material is blended with glassevaporated in an oxidizing atmosphere. For example, SiO₂ can beintroduced into Al₂O₃ to modify the physical properties (such asflexibility, fracture toughness) of the ceramic layer.

In some implementations, the ceramic separator layer 130 comprises aplurality of ceramic columnar projections. The ceramic columnar shapedprojections may have a diameter that expands from the bottom (e.g.,where the columnar shaped projection contacts the porous substrate) ofthe columnar shaped projection to a top of the columnar shapedprojection. The ceramic columnar projections typically comprisedielectric grains. Nano-structured contours or channels are typicallyformed between the dielectric grains.

In some implementations, the plurality of ceramic columnar projectionsmay comprise one or more of various forms of porosities. In someimplementations, the columnar projections of the ceramic separator layer130 form a nano-porous structure between the columnar projections ofdielectric material. In one implementation, the nano-porous structuremay have a plurality of nano-pores that are sized to have an averagepore size or diameter less than about 10 nanometers (e.g., from about 1nanometer to about 10 nanometers; from about 3 nanometers to about 5nanometers). In another implementation, the nano-porous structure mayhave a plurality of nano-pores sized to have an average pore size ordiameter less than about 5 nanometers. In one implementation, thenano-porous structure has a plurality of nano-pores having a diameterranging from about 1 nanometer to about 20 nanometers (e.g., from about2 nanometers to about 15 nanometers; or from about 5 nanometers to about10 nanometers). The nano-porous structure yields a significant increasein the surface area of the ceramic separator layer 130. The pores of thenanoporous structure can act as liquid electrolyte reservoir andprovides excess surface area for ion-conductivity. Not to be bound bytheory but it is believed that the electrolyte liquid/gel confinedwithin the nanoporous structure behaves similar to solid electrolyte.

In some implementations, the ceramic separator layer 130 has a porosityof at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or65% as compared to a solid film formed from the same material and aporosity up to at least 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, or 70% as compared to a solid film formed from the samematerial.

Porosity is typically used since it is easy to estimate. However,tortuosity is the direct measure for describing a lithium diffusionpathway. Tortuosity describes the tortuous path for Li diffusion inporous media. For example, if diffusion is along a straight pathway, thetortuosity equals 1. Tortuosity is not easily measured due to thecomplex geometry in dielectric layers (i.e., irregular particle shapes,wide particle size distribution, etc.). It is believed that directengineering tortuosity, i.e., introducing “straight” pathway orchannels, is desirable. Ceramic layers formed using the evaporationprocesses disclosed herein exhibit lower tortuosity when compared withceramic layers formed using currently know slot-die techniques or otherslurry deposition techniques.

The ceramic separator layer 130 may be a coating or a discrete layer,either having a thickness in the range of 1 nanometer to 3,000nanometers (e.g., in the range of 10 nanometers to 600 nanometers; inthe range of 50 nanometers to 200 nanometers; in the range of 100nanometers to 150 nanometers).

FIG. 2 illustrates a cross-sectional view of another implementation of acell structure 200 formed according to implementations described herein.In some implementations, the cell structure 200 is a Li-ion batterystructure. Similar to cell structure 100, the cell structure 200 has theceramic separator layer 130 formed according to implementationsdescribed herein. However, in addition the ceramic separator layer 130,the cell structure 200 also comprises one or more gel polymer layers 210a, 210 b (collectively 210) positioned between the ceramic separatorlayer 130 and the opposing electrode structure, which in thisimplementation is the negative electrode 140 a. Although shown ascontacting the positive electrode 120 b, it should be understood that insome implementations, the ceramic separator layer 130 a contacts thenegative electrode 140 a and the gel polymer layer 210 a contacts thenegative electrode 140 a. Not to be bound by theory, but it is believethat the gel polymer layer helps improve adhesion between the positiveelectrode and the negative electrode when joined together.

The polymer for the gel polymer layer 210 can be chosen from polymerscurrently used in the Li-ion battery industry. Examples of polymers thatmay be used to form the gel polymer layer include, but are not limitedto, polyvinylidene difluoride (PVDF), polyethylene oxide (PEO),poly-acrylonitrile (PAN), carboxymethyl cellulose (CMC), styrenebutadiene rubber (SBR), and combinations thereof. Not to be bound bytheory but it is believed that the gel polymer layer 210 can take-upLi-conducting electrolyte to form gel during device fabrication which isbeneficial for forming good solid electrolyte interface (SEI) and alsohelps lower resistance. In some implementations, gel electrolyte orliquid crystal electrolyte is made by using mixture of warm liquids andlithium ion conducting salt. The mixture of warm liquids is injectedinto the spiral-wound electrodes or stacked electrodes filling thenetwork electrode pores and the electrolyte forms a solid or gel at roomtemperature. The gel polymer layer 210 can be formed by dip-coating,slot-die coating, gravure coating, or printing. The polymer can also bedeposited using Applied Materials Metacoat equipment. The dielectricpolymer layer may have a thickness from about 5 nanometers to about 1micrometer. Organic polymers with sulfur ions (e.g., polyphenylenesulfide with Li₂O mixture) have shown good results for lithium metalbased anodes and in some cases form liquid crystal electrolyte.

FIG. 3 illustrates a cross-sectional view of another implementation of acell structure 300 formed according to implementations described herein.In some implementations, the cell structure 300 is a Li-ion batterystructure. Similar to cell structure 200, the cell structure 300 has oneor more ceramic separator layers 330 a-c (collectively 330) and one ormore gel polymer layers 310 a, 310 b (collectively 310) formed accordingto implementations described herein. The one or more ceramic separatorlayers 330 are similar to the one or more ceramic separator layers 130.The one or more gel polymer layers 310 are similar to the one or moregel polymer layers 210. However, the gel polymer layer 310 a ispositioned between or “sandwiched” in between the ceramic separatorlayer 330 a and the ceramic separator layer 330 b.

FIG. 4 illustrates a cross-sectional view of yet another implementationof a cell structure 400 formed according to one or more implementationsdescribed herein. In some implementations, the cell structure 400 is aLi-ion battery structure. Similar to cell structure 300, the cellstructure 400 has one or more ceramic separator layers 430 a-c(collectively 430) and one or more gel polymer layers 440 a, 440 b(collectively 440) formed according to implementations described herein.The one or more ceramic separator layers 430 are similar to the one ormore ceramic separator layer(s) 130. The one or more gel polymer layers440 a, 440 b (collectively 440) are similar to the one or more gelpolymer layers 210. However, the gel polymer layer 440 a is positionedbetween or “sandwiched” in between the ceramic separator layer 430 a andthe ceramic separator layer 430 b. The cell structure 400 optionallyincludes a pre-lithiation layer 410, and a protective film 420 formedbetween a ceramic separator layer 430 and the pre-lithiation layer 410.Thus, instead of depositing the ceramic separator layer directly on thenegative electrode as depicted in FIGS. 1-3, the ceramic separator layer430 is deposited directly on either the protective film 420 (if present)or the pre-lithiation layer 410 if the protective film 420 is notpresent.

In some implementations, the pre-lithiation layer 410 formed on thenegative electrode 140 a is a lithium metal film. The lithium metal filmmay be formed according to the implementations described herein. In someimplementations, the negative electrode 140 a is a silicon graphiteanode or a silicon oxide graphite anode with the lithium metal filmformed thereon. The lithium metal film replenishes lithium lost fromfirst cycle capacity loss of the negative electrode 140 a. The lithiummetal film may be a thin lithium metal film (e.g., 20 microns or less;from about 1 micron to about 20 microns; or from about 2 microns toabout 10 microns). In some implementations where the lithium metal filmfunctions as the negative electrode, the lithium metal film replaces thenegative electrode 140. In some implementations where the lithium metalfilm functions as the negative electrode the lithium metal film isformed on the negative current collector 150.

In some implementations, a protective film 420 is formed on the lithiummetal film. The protective film 420 is typically formed ex-situ on thelithium metal film. The protective film 420 is electrically insulatingyet sufficiently conductive to lithium-ions. In one implementation, theprotective film 420 is a nonporous film. In another implementation, theprotective film 420 is a porous film. In one implementation, theprotective film 420 has a plurality of nanopores that are sized to havean average pore size or diameter less than about 10 nanometers (e.g.,from about 1 nanometer to about 10 nanometers; from about 3 nanometersto about 5 nanometers). In another implementation, the protective film420 has a plurality of nanopores that are sized to have an average poresize or diameter less than about 5 nanometers. In one implementation,the protective film 420 has a plurality of nanopores having a diameterranging from about 1 nanometer to about 20 nanometers (e.g., from about2 nanometers to about 15 nanometers; or from about 5 nanometers to about10 nanometers).

The protective film 420 may be a coating or a discrete layer, eitherhaving a thickness in the range of 1 nanometer to 200 nanometers (e.g.,in the range of 5 nanometers to 200 nanometers; in the range of 10nanometers to 50 nanometers). Not to be bound by theory, but it isbelieved that protective films greater than 200 nanometers may increaseresistance within the rechargeable battery.

Examples of materials that may be used to form the protective film 420include, but are not limited to, lithium fluoride (LiF), aluminum oxide,lithium carbonate (Li₂CO₃), and combinations thereof. In oneimplementation, the protective film 420 is a lithium fluoride film. Notto be bound by theory but it is believed that the protective film 420can take-up Li-conducting electrolyte to form gel during devicefabrication which is beneficial for forming good solid electrolyteinterface (SEI) and also helps lower resistance. The protective film 420can be directly deposited on the lithium metal film by Physical VaporDeposition (PVD), such as evaporation or sputtering, special atomiclayer deposition (ALD), a slot-die process, a thin-film transferprocess, or a three-dimensional lithium printing process. PVD is apreferred method for deposition of the protective film 420. Theprotective film 420 can also be deposited using Metacoat equipment.

The ceramic separator layer 430 a may be deposited directly on eitherthe protective film 420 (if present) or the pre-lithiation layer 410 ifthe protective film 420 is not present. The ceramic separator layer 430a may be a lithium-ion conducting material. The lithium-ion conductingmaterial may be a lithium-ion conducting ceramic or a lithium-ionconducting glass. The Li-ion conducting material may be comprised of oneor more of LiPON, doped variants of either crystalline or amorphousphases of Li₇La₃Zr₂O₁₂, doped anti-perovskite compositions, Li₂S—P₂S₅,Li₁₀GeP₂S₁₂, and Li₃PS₄, lithium phosphate glasses, (1−x)LiI-(x)Li₄SnS₄,xLiI-(1−x)Li₄SnS₄, mixed sulfide and oxide electrolytes (crystallineLLZO, amorphous (1−x)LiI-(x)Li₄SnS₄ mixture, and amorphousxLiI-(1−x)Li₄SnS₄) for example. In one implementation, x is between 0and 1 (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9). TheLi-ion conducting material can be directly deposited on thepre-lithiation layer 410 or the protective film 420 using either a byPhysical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), spray,doctor blade, printing or any of a number of coating methods. A suitablemethod for some implementations is PVD. In some implementations, theceramic separator layer 430 a does not need to be ion conducting,however, once filled with electrolyte (liquid, gel, solid, combinationetc.), the combination of porous substrate and electrolyte is ionconducting.

In one implementation, the ceramic separator layer 430 a is thelithium-ion conducting material and the lithium-ion conducting materialis selected from the group consisting of: LiPON, crystalline oramorphous phases of garnet-type Li₇La₃Zr₂O₁₂, LISICON (e.g.,Li_(2+2x)Zn_(1−x)GeO₄ wherein 0<x<1), NASICON (e.g.,Na_(1+x)Zr₂SixP_(3−x)O₁₂ wherein 0<x<3), lithium borohydride (LiBH₄),doped anti-perovskite compositions, lithium containing sulfides (e.g.,Li₂S, Li₂S—P₂S₅, Li₁₀GeP₂S₁₂ and Li₃PS₄), and lithium argyrodites (e.g.,LiPS₅X wherein x is CI, Br or I).

In some implementations, the ceramic separator layer 430 a formed overthe negative electrode 140 and the ceramic separator layer 430 b formedover the positive electrode 120 are different materials. For example, inone implementation, ceramic separator layer 430 a is a non-porouslithium ion conducting material and the ceramic separator layer 430 b isa porous lithium ion conducting material.

In some implementations, the ceramic separator layer 430 is a non-porousion conducting electrolyte layer, which may provide addedelectrochemical stability for some anode material compositions. Forexample, in one implementation, the negative electrode 140 is a siliconor silicon oxide blended graphite anode material with the pre-lithiationlayer 410 (e.g., lithium metal film) formed thereon, a protective film420 that is a lithium fluoride film, and the ceramic separator layer 430is a non-porous lithium ion-conducting material.

In some implementations, prior to method 500 (see FIG. 5), method 600(see FIG. 6) or method 700 (see FIG. 7), the surfaces of the electrode(e.g., negative electrode and/or positive electrode) are optionallyexposed to a surface modification treatment to enhance thenucleation/growth conditions of the surfaces of the electrode. In someimplementations, the surface modification treatment process is a plasmatreatment process (e.g., corona discharge treatment process). Thesurface modification treatment process includes supplying a treatmentgas mixture into a processing region. A plasma is then formed from thetreatment gas mixture to plasma treat a surface of the electrode toactivate at least a portion of the electrode into an excited state,forming a treated electrode having a treated upper surface, which maythen enhance the nucleation/growth conditions of the subsequentlydeposited ceramic separator layer.

In one implementation, the treatment gas mixture includes at least oneof oxygen-containing gas, an inert gas (e.g., argon, helium), orcombinations thereof. In one implementation, the oxygen-containing gassupplied into the processing region includes at least one of oxygen(O₂), ozone (O₃), oxygen radicals (O*), ionized oxygen atoms, carbondioxide (CO₂), nitric oxide (NO_(x)), water vapor, or combinationsthereof. Other oxygen-containing gases may be used.

According to one implementation of the present disclosure involvingoxidation, a gas source supplies oxygen gas (O₂) through a mass flowcontroller to an ozonator, which converts a large fraction of the oxygento ozone gas (O₃). The resultant oxygen-based mixture of O₂ and O₃ andperhaps some oxygen radicals O* and ionized oxygen atoms or molecules isdelivered into the processing region. The oxygen-based gas reacts withinthe processing region with the surface of the electrode, which has beenheated to a predetermined, preferably low temperature. Ozone is ametastable molecule which spontaneously quickly dissociates in thereaction O₃→O₂+O*, where O* is a radical, which very quickly reacts withwhatever available material can be oxidized. The ozonator may beimplemented in a number of forms including capacitively or inductivelycoupled plasma or a UV lamp source.

At these high ozone concentrations, the electrode need not be heatedvery much to achieve relatively high oxidation rates. The high ozoneconcentration also allows the ozone partial pressure to be reduced. Thehigh ozone fraction allows the ozone oxidation to be performed atpressures of less than 20 Torr. It should be understood that theaforementioned surface modification technique is exemplary and othersurface modifications techniques that achieve the selected surfacemodification may be used. For example, in some implementations, thispreparation may include exposing the electrode to a corona treatment,chemically treating it (e.g. with an oxidizing agent), or adsorbing orgrafting a polyelectrolyte to the surface of the electrode. Having acharged electrode may be appropriate for a first layer of oppositelycharged material to bind to the electrode.

In some implementations, the surface modification treatment process isan electron beam treatment process. An electron beam source is directedonto a surface of the electrode prior to coating the electrode. Theelectron beam source may be a linear source. The electron beam deviceemitting the electron beam is typically adapted such that the electronbeam affects the electrode across its entire width, such that due to thelongitudinal movement of the electrode, the whole surface (on one side)of the electrode is treated with the electron beam. The electron beamdevice may for example be an electron source such as an electron floodgun, a linear electron gun, an electron beam, or the like. The gas usedin the electron source may be Argon, O₂, N₂, CO₂, or He, moreparticularly O₂, N₂, CO₂, or He.

The electrode treated with the emitted electrons is physically,respectively structurally altered in order to achieve improved adhesionbetween the electrode and the subsequently deposited ceramic separatorlayer. The selected effect can be achieved by providing electrons atenergies from 1 keV to 15 keV, more typically from 5 keV to 10 keV, forexample, 6 keV, 7 keV, 8 keV or 9 keV. Typical electron currents arefrom 20 mA to 1500 mA, for example 500 mA.

In some implementations prior to method 500 (see FIG. 5), method 600(see FIG. 6), method 700 (see FIG. 7), or method 800 (see FIG. 8), thesurfaces of the electrode (e.g., negative electrode and/or positiveelectrode) is optionally exposed to a cooling process. In oneimplementation, the surfaces of the electrode structure may be cooled toa temperature between −20 degrees Celsius and room temperature (i.e., 20to 22 degrees Celsius) (e.g., −10 degrees Celsius and 0 degreesCelsius). In some implementations, the electrode structure may be cooledby cooling the drum over which the electrode structure travels. Otheractive cooling means may be used to cool the electrode structure. Duringthe evaporation process, the electrode structure may be exposed totemperatures in excess of 1,000 degrees Celsius thus it is beneficial tocool the electrode structure prior to the evaporation processes ofoperation 510, operation 610, and operation 710.

FIG. 5 illustrates a process flow chart summarizing one implementationof a method 500 for forming a cell structure according to one or moreimplementations described herein. The cell structure may be, forexample, the cell structure 100 depicted in FIG. 1.

At operation 510, the material to be deposited on at least one of asurface of a negative electrode and a surface of a positive electrode isexposed to an evaporation process to evaporate the material to bedeposited in a processing region. In some implementations, the negativeelectrode is negative electrode 140 and the positive electrode ispositive electrode 120. In some implementations, the material to bedeposited is deposited on a single electrode (e.g., either the negativeelectrode or the positive electrode). In some implementations, thematerial to be deposited is deposited on both the negative electrode andthe positive electrode. In some implementations, deposition on thenegative electrode and the positive electrode may occur in the sameprocessing chamber or may occur in separate processing chambers. In someimplementations, deposition on the negative electrode and the positiveelectrode may occur sequentially or simultaneously.

The evaporation material may be chosen from the group consisting ofaluminum (Al), zirconium (Zr), hafnium (Hf), niobium (Nb), tantalum(Ta), titanium (Ti), yttrium (Y), lanthanum (La), silicon (Si), boron(B), silver (Ag), chromium (Cr), copper (Cu), indium (In), iron (Fe),magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), nickel (Ni),tin (Sn), ytterbium (Yb), lithium (Li), calcium (Ca) or combinationsthereof. Typically, the material to be deposited is a metal such asaluminum or an aluminum alloy. Further, the evaporation material mayalso be an alloy of two or more metals. The evaporation material is thematerial that is evaporated during the evaporation and with which thesurface(s) of the one or more electrodes are coated. The material to bedeposited (e.g., aluminum) can be provided in a crucible. The aluminumcan, for example, be evaporated by thermal evaporation techniques or byelectron beam evaporation techniques.

In some implementations, the evaporation material is fed to the crucibleas a wire. In this case, the feeding rates and/or the wire diametershave to be chosen such that the appropriate ratio of the evaporationmaterial and the reactive gas is achieved. In some implementations, thediameter of the feeding wire for feeding to the crucible is chosenbetween 0.5 mm and 2.0 mm (e.g., between 1.0 mm and 1.5 mm). Thesedimensions may refer to several feedings wires made of the evaporationmaterial. Typical feeding rates of the wire are in the range of between50 cm/min and 150 cm/min (e.g., between 70 cm/min and 100 cm/min).

The crucible is heated in order to generate a vapor, which reacts withthe reactive gas supplied at operation 510 to coat the surface(s) of theone or more electrodes with a ceramic separator layer (e.g., ceramicseparator layer 130). Typically, the crucible is heated by applying avoltage to the electrodes of the crucible, which are positioned atopposite sides of the crucible. Generally, according to implementationsdescribed herein, the material of the crucible is conductive. Typically,the material used as crucible material is temperature resistant to thetemperatures used for melting and evaporating. Typically, the crucibleof the present disclosure is made of one or more materials selected fromthe group consisting of metallic boride, metallic nitride, metalliccarbide, non-metallic boride, non-metallic nitride, non-metalliccarbide, nitrides, titanium nitride, borides, graphite, TiB₂, BN, B₄C,and SiC.

The material to be deposited is melted and evaporated by heating theevaporation crucible. Heating can be conducted by providing a powersource (not shown) connected to the first electrical connection and thesecond electrical connection of the crucible. For instance, theseelectrical connections may be electrodes made of copper or an alloythereof. Thus, heating is conducted by the current flowing through thebody of the crucible. According to other implementations, heating mayalso be conducted by an irradiation heater of an evaporation apparatusor an inductive heating unit of an evaporation apparatus.

The evaporation unit according to the present disclosure is typicallyheatable to a temperature of between 1,300 degrees Celsius and 1,600degrees Celsius, such as 1,560 degrees Celsius. This is done byadjusting the current through the crucible accordingly, or by adjustingthe irradiation accordingly. Typically, the crucible material is chosensuch that its stability is not negatively affected by temperatures ofthat range. Typically, the speed of the one or more electrodes is in therange of between 20 cm/min and 200 cm/min, more typically between 80cm/min and 120 cm/min such as 100 cm/min. In these cases, the means fortransporting should be capable of transporting the substrate at thosespeeds.

At operation 520, a reactive gas is flowed into the processing regionfor reacting with the evaporated material to form a ceramic separatorlayer on at least a surface of the negative electrode and a surface ofthe positive electrode. According to typical implementations, which canbe combined with other implementations described herein, the reactivegases can be selected from the group consisting of: oxygen-containinggases, nitrogen-containing gases, or combinations thereof. Exemplaryoxygen-containing gases that may be used with the implementationsdescribed herein include oxygen (O₂), ozone (O₃), oxygen radicals (O*),ionized oxygen atoms, carbon dioxide (CO₂), nitric oxide (NO_(x)), watervapor, or combinations thereof. Exemplary nitrogen containing gases thatmay be used with the implementations described herein include N₂, N₂O,NO₂, NH₃, or combinations thereof. According to yet furtherimplementations, additional gases, typically inert gases such as argoncan be added to a gas mixture comprising the reactive gas. Thereby,typically the amount of reactive gas can be more easily controlled.According to typical implementations, which can be combined with otherimplementations described herein, the process can be carried out in avacuum environment with a typical atmosphere of 1*10⁻² mbar to 1*10⁻⁶mbar (e.g., 1*10⁻³ mbar or below; 1*10⁻⁴ mbar or below).

At operation 520, in some implementations, moist oxygen may be used asthe reactive gas. The moist oxygen may be formed by flowing oxygenthrough a canister containing water vapor to react with the evaporatedmaterial to form an aluminum hydroxide oxide ((AlO(OH)), which isdeposited on the surface of the electrode. The aluminum hydroxide oxide((AlO(OH)) typically takes the form of diaspore ((α-AlO(OH))), boehmite(γ-AlO(OH)), or akdalaite (5Al₂O₃.H₂O). Not to be bound by theory butnot only is the aluminum hydroxide oxide thermodynamically stable butthe hydrogen bond also helps improve the bond strength of the ceramicseparator layer to the surface of the electrode.

In some implementations, during operation 520, a plasma is formed fromthe reactive gas mixture. In some implementations, the plasma is anoxygen-containing plasma. The oxygen-containing plasma reacts with theevaporated material to deposit the ceramic separator layer on thesurface of the electrode. In one implementation, the reactive gasmixture includes at least one of oxygen-containing gas, an inert gas(e.g., argon, helium), or combinations thereof. In one implementation,the oxygen-containing gas supplied into the processing region includesat least one of oxygen (O₂), ozone (O₃), oxygen radicals (O*), ionizedoxygen atoms, carbon dioxide (CO₂), nitric oxide (NO_(x)), water vapor,or combinations thereof. Other oxygen-containing gases may be used. Insome implementations, the plasma is formed using a remote plasma sourceand delivered to the processing region.

In some implementations, during operation 520, a gas source suppliesoxygen gas (O₂) through a mass flow controller to an ozonator, whichconverts a large fraction of the oxygen to ozone gas (O₃). The resultantoxygen-based mixture of O₂ and O₃ and perhaps some oxygen radicals O*and ionized oxygen atoms or molecules is delivered into the processingregion. The oxygen-based gas reacts within the processing region withthe surface of electrode structure, which has been heated to apredetermined, preferably low temperature. Ozone is a metastablemolecule which spontaneously quickly dissociates in the reactionO₃→O₂+O*, where O* is a radical, which very quickly reacts with whateveravailable material can be oxidized. The ozonator may be implemented in anumber of forms including capacitively or inductively coupled plasma ora UV lamp source.

In some implementations, where at least one edge of the positiveelectrode and/or the negative electrode remains exposed, it may bedesirable to deposit an additional ceramic edge coating on the exposededge to avoid shorting. The ceramic edge coating may contain the samematerial as the ceramic separator layer. The ceramic edge coating may bedeposited using wet deposition methods (e.g., slot-die coating) followedby optional drying and/or calendaring operations. The ceramic edgecoating typically has a thickness similar to the ceramic separatorlayer. In one implementation, the edge coating process occurs prior tooperation 510. In another implementation, the edge coating process takesplace after operation 520.

At operation 530, the negative electrode and the positive electrode arejoined together with the ceramic separator layer therebetween to form acell structure, for example, cell structure 100.

FIG. 6 illustrates a process flow chart summarizing one implementationof a method 600 for forming a cell structure according to one or moreimplementations described herein. The cell structure may be, forexample, the cell structure 200 depicted in FIG. 2. Method 600 issimilar to method 500 except that method 600 includes operation 630where a gel polymer layer is deposited on the surface of either thenegative electrode or the surface of the positive electrode. In someimplementations, the gel polymer layer is gel polymer layer 210. In someimplementations, the negative electrode is negative electrode 140 andthe positive electrode is positive electrode 120. In someimplementations, the ceramic separator layer 130 is deposited on asingle electrode (e.g., either the negative electrode or the positiveelectrode) and the gel polymer layer 210 is deposited on the otherelectrode prior to joining the electrodes together.

At operation 610, the material to be deposited on at least one of asurface of a negative electrode and a surface of a positive electrode isexposed to an evaporation process to evaporate the material to bedeposited in a processing region. Operation 610 may be performedsimilarly to operation 510. At operation 620, a reactive gas is flowedinto the processing region for reacting with the evaporated material toform a ceramic separator layer on at least a surface of the negativeelectrode and a surface of the positive electrode. Operation 620 may beperformed similarly to operation 520.

At operation 630, a gel polymer layer is deposited on at least one ofthe surface of the negative electrode and the surface of the positiveelectrode. The polymer for the gel polymer layer 210 can be chosen frompolymers currently used in the Li-ion battery industry. Examples ofpolymers that may be used to form the gel polymer layer include, but arenot limited to, polyvinylidene difluoride (PVDF), polyethylene oxide(PEO), poly-acrylonitrile (PAN), carboxymethyl cellulose (CMC), styrenebutadiene rubber (SBR), and combinations thereof. Not to be bound bytheory but it is believed that the gel polymer layer 210 can take-upLi-conducting electrolyte to form gel during device fabrication which isbeneficial for forming good solid electrolyte interface (SEI) and alsohelps lower resistance. The gel polymer layer 210 can be formed bydip-coating, slot-die coating, gravure coating, or printing. The polymercan also be deposited using Applied Materials Metacoat equipment. Thedielectric polymer layer may have a thickness from about 5 nanometers toabout 1 micrometer.

At operation 640, the negative electrode and the positive electrode arejoined together with the ceramic separator layer and gel polymer layerthere between to form a cell structure, for example, cell structure 200.

FIG. 7 illustrates a process flow chart summarizing one implementationof a method 700 for forming a cell structure according to one or moreimplementations described herein. The cell structure may be, forexample, the cell structure 300 depicted in FIG. 3. Method 700 issimilar to method 600 except that ceramic separator layers are depositedon both the positive electrode and the negative electrode with a gelpolymer layer deposited on one of the ceramic separator layers prior tojoining the negative electrode and the positive electrode together. Insome implementations, the gel polymer layer is gel polymer layer 310 a,the first ceramic separator layer is ceramic separator layer 330 a andthe second ceramic separator layer is ceramic separator layer 330 b. Insome implementations, the negative electrode is negative electrode 140and the positive electrode is positive electrode 120.

At operation 710, the material to be deposited on at least one of asurface of a negative electrode and a surface of a positive electrode isexposed to an evaporation process to evaporate the material to bedeposited in a processing region. Operation 710 may be performedsimilarly to operation 510 and operation 610. At operation 720, areactive gas is flowed into the processing region for reacting with theevaporated material to form a first ceramic separator layer on a surfaceof the negative electrode and a second ceramic separator layer on asurface of the positive electrode. In some implementations, depositionon the negative electrode and the positive electrode may occur in thesame processing chamber or may occur in separate processing chambers. Insome implementations, deposition on the negative electrode and thepositive electrode may occur sequentially or simultaneously. Operation720 may be performed similarly to operation 520 and operation 620.

At operation 730, a gel polymer layer is deposited on at least one ofthe first ceramic separator layer and the second ceramic separatorlayer. The polymer for the gel polymer layer 310 can be chosen frompolymers currently used in the Li-ion battery industry. Examples ofpolymers that may be used to form the gel polymer layer include, but arenot limited to, polyvinylidene difluoride (PVDF), polyethylene oxide(PEO), poly-acrylonitrile (PAN), carboxymethyl cellulose (CMC), styrenebutadiene rubber (SBR), and combinations thereof. The polymer can alsobe a liquid crystal with salt such as Li₂O. Not to be bound by theorybut it is believed that the gel polymer layer 310 can take-upLi-conducting electrolyte to form gel during device fabrication which isbeneficial for forming good solid electrolyte interface (SEI) and alsohelps lower resistance. The gel polymer layer 310 can be formed bydip-coating, slot-die coating, gravure coating, or printing. The polymercan also be deposited using Applied Materials Metacoat equipment. Thedielectric polymer layer may have a thickness from about 5 nanometers toabout 1 micrometer.

At operation 740, the negative electrode and the positive electrode arejoined together with the first ceramic separator layer, the gel polymerlayer, and the second ceramic separator layer there between to form acell structure, for example, cell structure 300.

FIG. 8 illustrates a process flow chart summarizing one implementationof a method 800 for forming an electrode structure according to one ormore implementations described herein. The cell structure may be, forexample, the cell structure 400 depicted in FIG. 4. At operation 810, anegative electrode is provided. The negative electrode structure may benegative electrode 140.

At operation 820, a lithium metal layer is formed on the negativeelectrode. The lithium metal layer may be the pre-lithiation layer 410.In one implementation, the alkali metal film is formed on the substrate.In some implementations, if the negative electrode 140 is alreadypresent, the pre-lithiation layer 410 is formed on the negativeelectrode 140. If the negative electrode 140 is not present, the lithiummetal film may be formed directly on the negative current collector 150.Any suitable lithium metal film deposition process for depositing thinfilms of lithium metal may be used to deposit the thin film of lithiummetal. Deposition of the thin film of lithium metal may be by PVDprocesses, such as evaporation, a slot-die process, a transfer process,screen printing or a three-dimensional lithium printing process. Thechamber for depositing the thin film of alkali metal may include a PVDsystem, such as an electron-beam evaporator, a thermal evaporator, or asputtering system, a thin film transfer system (including large areapattern printing systems such as gravure printing systems) or a slot-diedeposition system.

At operation 830, a protective layer is optionally formed on the lithiummetal layer. The protective layer may be protective film 420. Theprotective film 420 may be a lithium fluoride film or a lithiumcarbonate film. In one implementation, the protective film 420 is formedvia an evaporation process. The material to be deposited on thesubstrate is exposed to an evaporation process to evaporate the materialto be deposited in a processing region. The evaporation material may bechosen from the group consisting of lithium (Li), lithium fluoride (LiF)(e.g., ultra-high pure single crystal lithium), aluminum oxide(AlO_(x)), lithium carbonate (Li₂CO₃), or combinations thereof.Typically, the material to be deposited includes a metal such aslithium. Further, the evaporation material may also be an inorganiccompound. The evaporation material is the material that is evaporatedduring the evaporation process and with which the lithium metal film iscoated. The material to be deposited (e.g., lithium fluoride) can beprovided in a crucible. The lithium fluoride for example, can beevaporated by thermal evaporation techniques or by electron beamevaporation techniques. This AlO_(x) could be nm thick but can benon-porous. Under some electrochemical conditions ion conducting Li—Al—Omay form.

In some implementations, the evaporation material is fed to crucible inpellet format. In some implementations, the evaporation material is fedto the crucible as a wire. In this case, the feeding rates and/or thewire diameters have to be chosen such that the sought after ratio of theevaporation material and the reactive gas is achieved. In someimplementations, the diameter of the feeding wire for feeding to thecrucible is chosen between 0.5 mm and 2.0 mm (e.g., between 1.0 mm and1.5 mm). These dimensions may refer to several feedings wires made ofthe evaporation material. Typical feeding rates of the wire are in therange of between 50 cm/min and 150 cm/min (e.g., between 70 cm/min and100 cm/min).

The crucible is heated in order to generate a vapor to coat the lithiummetal film with the protective film. Typically, the crucible is heatedby applying a voltage to the electrodes of the crucible, which arepositioned at opposite sides of the crucible. Generally, according toimplementations described herein, the material of the crucible isconductive. Typically, the material used as crucible material istemperature resistant to the temperatures used for melting andevaporating. Typically, the crucible of the present disclosure is madeof one or more materials selected from the group consisting of metallicboride, metallic nitride, metallic carbide, non-metallic boride,non-metallic nitride, non-metallic carbide, nitrides, titanium nitride,borides, graphite, tungsten, TiB₂, BN, B₄C, and SiC.

The material to be deposited is melted and evaporated by heating theevaporation crucible. Heating can be conducted by providing a powersource (not shown) connected to the first electrical connection and thesecond electrical connection of the crucible. For instance, theseelectrical connections may be electrodes made of copper or an alloythereof. Thus, heating is conducted by the current flowing through thebody of the crucible. According to other implementations, heating mayalso be conducted by an irradiation heater of an evaporation apparatusor an inductive heating unit of an evaporation apparatus.

The evaporation unit according to the present disclosure is typicallyheatable to a temperature of between 800 degrees Celsius and 1200degrees Celsius, such as 845 degrees Celsius. This is done by adjustingthe current through the crucible accordingly, or by adjusting theirradiation accordingly. Typically, the crucible material is chosen suchthat its stability is not negatively affected by temperatures of thatrange. Typically, the speed of the porous polymeric substrate is in therange of between 20 cm/min and 200 cm/min, more typically between 80cm/min and 120 cm/min such as 100 cm/min. In these cases, the means fortransporting should be capable of transporting the substrate at thosespeeds.

At operation 840, the material to be deposited on at least one of asurface of the lithium metal layer and/or a surface of the protectivelayer is exposed to an evaporation process to evaporate the material tobe deposited in a processing region. Operation 810 may be performedsimilarly to operation 510, operation 610, and operation 710. Atoperation 850, a reactive gas is flowed into the processing region forreacting with the evaporated material to form a ceramic separator layeron at least one of a surface of the lithium metal layer and/or a surfaceof the protective layer. The ceramic separator layer may be ceramicseparator layer 430 a. In some implementations, deposition on thenegative electrode and the positive electrode may occur in the sameprocessing chamber or may occur in separate processing chambers. In someimplementations, deposition on the negative electrode and the positiveelectrode may occur sequentially or simultaneously. Operation 720 may beperformed similarly to operation 520 and operation 620.

Optionally a gel polymer layer is formed on the ceramic separator layer.The gel polymer layer may be gel polymer layer 440 and may be formedsimilarly to gel polymer layer 310 described at operation 730. Thepolymer for the gel polymer layer 440 can be chosen from polymerscurrently used in the Li-ion battery industry. Examples of polymers thatmay be used to form the gel polymer layer include, but are not limitedto, polyvinylidene difluoride (PVDF), polyethylene oxide (PEO),poly-acrylonitrile (PAN), carboxymethyl cellulose (CMC), styrenebutadiene rubber (SBR), and combinations thereof. Not to be bound bytheory but it is believed that the gel polymer layer 440 can take-upLi-conducting electrolyte to form gel during device fabrication which isbeneficial for forming good solid electrolyte interface (SEI) and alsohelps lower resistance. The gel polymer layer 440 can be formed bydip-coating, slot-die coating, gravure coating, or printing. The polymercan also be deposited using Applied Materials Metacoat equipment. Thedielectric polymer layer may have a thickness from about 5 nanometers toabout 1 micrometer.

The negative electrode and the positive electrode are joined togetherwith the ceramic separator layer 430 a, the gel polymer layer 440 a, andthe ceramic separator layer 430 b there between to form a cellstructure, for example, cell structure 400.

FIG. 9 illustrates a schematic view of an integrated processing tool 900for forming a ceramic separator according to one or more implementationsdescribed herein. In certain implementations, the integrated processingtool 900 comprises a plurality of processing modules or chambers 920 and930 arranged in a line, each configured to perform one processingoperation to a continuous sheet of material 910. In one implementation,the processing chambers 920 and 930 are stand-alone modular processingchambers wherein each modular processing chamber is structurallyseparated from the other modular processing chambers. Therefore, each ofthe stand-alone modular processing chambers, can be arranged,rearranged, replaced, or maintained independently without affecting eachother. In certain implementations, the processing chambers 920 and 930are configured to process both sides of the continuous sheet of material910. Although the integrated processing tool 900 is configured toprocess a vertically oriented continuous sheet of material 910, theintegrated processing tool 900 may be configured to process substratespositioned in different orientations, for example, a horizontallyoriented continuous sheet of material 910. In certain implementations,the continuous sheet of material 910 is a flexible conductive substrate.

In certain implementations, the integrated processing tool 900 comprisesa transfer mechanism 905. The transfer mechanism 905 may comprise anytransfer mechanism capable of moving the continuous sheet of material910 through the processing region of the processing chambers 920 and930. The transfer mechanism 905 may comprise a common transportarchitecture. The common transport architecture may comprise areel-to-reel system with a take-up reel 914 and a feed reel 912 for thesystem. The take-up reel 914 and the feed reel 912 may be individuallyheated. The take-up reel 914 and the feed reel 912 may be individuallyheated using an internal heat source positioned within each reel or anexternal heat source. The common transport architecture may furthercomprise one or more intermediate transfer reels (913 a & 913 b, 916 a &916 b, 918 a & 918 b) positioned between the take-up reel 914 and thefeed reel 912. Although the integrated processing tool 900 is depictedas having a single processing region, in certain implementations, it maybe advantageous to have separate or discrete processing regions,modules, or chambers for each process. For implementations havingdiscrete processing regions, modules, or chambers, the common transportarchitecture may be a reel-to-reel system where each chamber orprocessing region has an individual take-up-reel and feed reel and oneor more optional intermediate transfer reels positioned between thetake-up reel and the feed reel. The common transport architecture maycomprise a track system. The track system extends through the processingregions or discrete processing regions. The track system is configuredto transport either a web substrate or discrete substrates.

The integrated processing tool 900 may comprise the feed reel 912 andthe take-up reel 914 for moving the continuous sheet of material 910through the different processing chambers. The different processingchamber may include a first processing chamber 920 for deposition of aceramic separator film and a second processing chamber 930 fordeposition of a gel polymer layer over the ceramic separator film. Insome implementations, the finished electrode will not be collected onthe take-up reel 914 as shown in the figures, but may go directly forintegration with the separator and positive electrodes, etc., to formbattery cells.

The first processing chamber 920 is configured for depositing a ceramicseparator film on the continuous sheet of material 910. In oneimplementation, the first processing chamber 920 is an evaporationchamber. The evaporation chamber has a processing region 942 that isshown to comprise an evaporation source 944 a, 944 b (collectively 944)that may be placed in a crucible, which may be a thermal evaporator oran electron beam evaporator (cold) in a vacuum environment, for example.A first gas source 950 for supplying reactive gas to the processingregion 942 is coupled with the processing region 942. A remote plasmasource 960 is coupled with the processing region for supplying plasma tothe processing region. The remote plasma source 960 may be coupled witha second gas source 970.

The second processing chamber 930 is configured for depositing a gelpolymer layer over the sheet of material (e.g., on the ceramic separatorfilm. The gel polymer layer may be an ion conducting material asdescribed herein. The gel polymer layer can be formed by dip-coating,slot-die coating, gravure coating, laminating, or printing.

In one implementation, the second processing chamber 930 is athree-dimensional printing chamber. The printing chamber has aprocessing region 952 that is shown to comprise a printing source 954 a,954 b (collectively 954) for printing a polymer ink.

In one implementation, the processing region 942 and the processingregion 952 remain under vacuum and/or at a pressure below atmosphereduring processing. The vacuum level of processing region 942 may beadjusted to match the vacuum level of the processing region 952. In oneimplementation, the processing region 942 and the processing region 952remain at atmospheric pressure during processing. In one implementation,the processing region 942 and the processing region 952 remain under aninert gas atmosphere during processing. In one implementation, the inertgas atmosphere is an argon gas atmosphere. In one implementation, theinert gas atmosphere is a nitrogen gas (N₂) atmosphere.

Additional chambers may be included in the integrated processing tool900. In some implementations, additional chambers may provide fordeposition of an electrolyte soluble binder, or in some implementations,additional chambers may provide for formation of electrode material(positive or negative electrode material). In some implementations,additional chambers provide for cutting of the electrode.

FIG. 10A illustrates a scanning electron microscope (SEM) image 1000 ofuncoated cathode material. FIG. 10B illustrates an SEM image 1010 ofcathode material coated with aluminum oxide according to implementationsdescribed herein.

FIG. 11 illustrates an SEM image of a schematic cross-sectional view ofa cell structure 1100 having a ceramic separator layer formed accordingto implementations described herein. The cell structure 1100 includes aceramic separator layer positioned between a negative electrode and apositive electrode. The negative electrode has a thickness of about 55μm and an estimated porosity of less than 20%. The positive electrode(e.g., LiCoO₂) has a thickness of about 65 μm and an estimated porosityof about 17%. The ceramic separator layer has a thickness of about 12 to14 μm.

In summary, some of the benefits of the present disclosure include theefficient deposition of ceramic separator material directly ontoelectrode material. The ability to deposit ceramic separator materialdirectly onto electrode material eliminates the need for polyolefinseparators. Elimination of the polyolefin separator reduces thelikelihood of thermal shrinkage while decreasing the distance betweenthe positive electrode and the negative electrode. For example, in someimplementations the ceramic separator layer formed according toimplementations described herein has a thickness of 3 μm or less incomparison with a polyolefin separate, which typically has a thicknessof about 20 μm or more. In addition, the dry coating techniquesdescribed herein do not suffer from several of the drawbacks that wetcoating techniques suffer from. For example, wet coating techniquesinclude solvents, which are often adsorbed into the underlying electrodestructure, which adds an extra drying operation to the overall process.Further, in some implementations described herein, the process ofceramic separator layer deposition is a vacuum coating process, whichremoves residual moisture from the electrode structure without adding anadditional drying component to the deposition process and the processingtool.

When introducing elements of the present disclosure or exemplary aspectsor implementation(s) thereof, the articles “a,” “an,” “the” and “said”are intended to mean that there are one or more of the elements.

The terms “comprising,” “including” and “having” are intended to beinclusive and mean that there may be additional elements other than thelisted elements.

While the foregoing is directed to implementations of the presentdisclosure, other and further implementations of the present disclosuremay be devised without departing from the basic scope thereof, and thescope thereof is determined by the claims that follow.

1. A method of forming an electrode structure, comprising: exposing ametallic material to be deposited over a surface of a lithium metallayer formed on a negative electrode structure positioned in aprocessing region to an evaporation process to form an evaporatedmetallic material; flowing a reactive gas into the processing region,comprising: exposing oxygen to water vapor to form moist oxygen; andintroducing the moist oxygen into the processing region; and reactingthe reactive gas and the evaporated metallic material to deposit aceramic layer on the surface of the lithium metal layer.
 2. The methodof claim 1, wherein the metallic material is selected from the groupconsisting of: aluminum (Al), silver (Ag), chromium (Cr), copper (Cu),indium (In), iron (Fe), magnesium (Mg), nickel (Ni), tin (Sn), ytterbium(Yb), or a combination thereof.
 3. The method of claim 1, wherein theceramic layer is an aluminum hydroxide oxide layer.
 4. The method ofclaim 1, wherein the evaporation process is a thermal evaporationprocess or an electron beam evaporation process.
 5. The method of claim1, wherein the evaporation process comprises exposing the metallicmaterial to a temperature of between 1,300 degrees Celsius and 1,600degrees Celsius.
 6. The method of claim 1, wherein the ceramic layer isa binder-free ceramic layer.
 7. The method of claim 1, wherein theceramic layer has a thickness in the range of 1 nanometer and 3,000nanometers.
 8. The method of claim 7, wherein the ceramic layer has athickness in the range of 10 nanometers to 500 nanometers.
 9. The methodof claim 1, wherein the ceramic layer comprises boehmite.
 10. The methodof claim 1, wherein the negative electrode structure is constructed fromgraphite or silicon-containing graphite.
 11. The method of claim 1,further comprising depositing a gel polymer layer on the ceramic layer.12. The method of claim 11, wherein the gel polymer layer is selectedfrom polyvinylidene difluoride (PVDF), polyethylene oxide (PEO),poly-acrylonitrile (PAN), carboxymethyl cellulose (CMC), styrenebutadiene rubber (SBR), or a combination thereof.
 13. The method ofclaim 1, wherein the lithium metal layer has a protective film formedthereon prior to exposing the metallic material and the protective filmis selected from lithium fluoride, lithium carbonate, or a combinationthereof.
 14. A method of forming a battery, comprising: depositing aceramic layer on a surface of a negative electrode structure,comprising: exposing a metallic material to be deposited on the surfaceof the negative electrode structure positioned in a processing region toan evaporation process to form an evaporated metallic material; flowinga reactive gas into the processing region; and reacting the reactive gasand the evaporated metallic material to deposit the ceramic layer on thesurface of the negative electrode structure, wherein flowing a reactivegas into the processing region comprises flowing moist oxygen into theprocessing region; and joining the negative electrode structure with apositive electrode structure with the ceramic layer therebetween. 15.The method of claim 14, wherein the ceramic layer is an aluminumhydroxide oxide layer.
 16. The method of claim 14, wherein theevaporation process is a thermal evaporation process or an electron beamevaporation process.
 17. A method of forming an electrode structure,comprising: transferring a continuous sheet of material from a feed reelthrough a first processing region containing a first evaporation source,wherein the continuous sheet of material comprises a negative electrodestructure; forming a ceramic layer over the continuous sheet ofmaterial, comprising: exposing the continuous sheet of material to anevaporated metallic material from the first evaporation source in thefirst processing region; and flowing a reactive gas into the firstprocessing region, comprising: exposing oxygen to water vapor to formmoist oxygen; and introducing the moist oxygen into the first processingregion; and reacting the reactive gas and the evaporated metallicmaterial to deposit the ceramic layer on the negative electrodestructure.
 18. The method of claim 17, further comprising: transferringthe continuous sheet of material through a second processing region; anddepositing a gel polymer film on the negative electrode structure in thesecond processing region.
 19. The method of claim 18, wherein themetallic material is selected from the group consisting of: aluminum(Al), silver (Ag), chromium (Cr), copper (Cu), indium (In), iron (Fe),magnesium (Mg), nickel (Ni), tin (Sn), ytterbium (Yb), or a combinationthereof.
 20. The method of claim 17, wherein the ceramic layer is analuminum hydroxide oxide layer.